By collecting soil samples from different altitude gradients ranging from 1916 m to 4335 m in the Kunlun Mountains, this study analyzed the content of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) in the 0-50 cm soil layer, as well as their ecological stoichiometric characteristics, and explored the variation patterns of soil nutrients and ecological stoichiometric characteristics with elevation in the Kunlun Mountains. Additionally, by analyzing the relationships between total soil salinity content, pH, aspect, slope, plant community coverage, height, and climate factors with soil nutrients and ecological stoichiometric characteristics, this study investigated the driving factors for the formation of soil nutrients and ecological stoichiometric characteristics in the Kunlun Mountains. The results showed that: (1) The content of SOC, TN, and TP exhibited a significant increasing trend with increasing altitude, although the change in TP content with altitude was relatively small, showing a slow increase. The soil C:N ratio did not vary with altitude, while the C:P and N:P ratios significantly increased as altitude rose. (2) SOC and TN content were primarily influenced by the maximum temperature in the hottest month, the seasonal temperature variation coefficient, and plant community coverage, while TP content was mainly affected by total soil salinity content, slope, and the maximum temperature in the hottest month. (3) The soil C:N ratio was mainly affected by plant community height, while the C:P and N:P ratios were primarily influenced by the seasonal temperature variation coefficient and plant community coverage. The findings of this study provide a foundation for further understanding the biogeochemical cycling characteristics of C, N, and P in mountain ecosystems.